Flexible shaft handpiece



l'June 15, 1926.

Filed Sept. 25, 1923 Patented June 15, 1926.

Lssas'a JOSEPH F KELLER, `OE"1\TE`W`Y(')EZK,'.`A1\'KD ALWIN B. BACHMANN, OF BROOKLYN, `NEW YORK, ASSIGNORS T0 KELLER IVIECBLNICAL ENGINEERING CORPORATION, OF BROOKLYN, NEW'YORK, A CORPORATION OF NEW YORK.

"'FLXBILE VSHAFT HANDPIECE.

l Aipxic'atibn fnedfsptember'zs;1923. 'serial No. 664,684.

Our inventionl 'relates inore particularly to a flexible shaft hand" pieceV for 'holding burrs or "grinding 1Wheels "operated tloya flexibleV shaft i bench grinder "or f the like, and to Aka highl'spee'df attaeh'nient, adapted to' be opeiated'in vconnection* tliereivith. V

Various' types 'f'ofllia'n'd' pie'c'esffare Well hall bearings, but'it islelievedtliat'in `"our improved hand '-piece, ive j have" 'overcome 'many of the' objections offp'ri'or hand' pieces and in addition yl'afe y:produced "a satisfao piece, which, We believe`,is novel. @ne ohject of Iour invention,therefore, "llas been ton'iakethe cylindrical hand piece coinpaet 'as possible and'this We liaveaccniplished by theCnipaGt arrangement ofthe cup and cone l ball l bearings, `v'which Aive have incorporated therein,

JIn'tloeordinary hand piece, the flexible the vrotatable clutch oftheliandpie'ce. T his c'onstru ctionV allbivs 'fer lloiig'fitudinal `play and "at all Etunes "is 'elfectrye to "niain `ain connection between' thenilexible sliaftljand they chuck Yand `it 'is foilnd 'in practice that it: does not 'Wear 'so' readily.

In `using 'sinall lluijrs or 'grinding Wheels, for inishing'dieser the like, it is desirable to run the tool'fat higllnspeed vand Lwhile this can 5 be vdene to f a Iliiiiited extent-'loyy the ordinary direct connection ofthe hand' piece vivith` 'the flexible shaft, `itis not desirable on account dfexcessive friction `Yin *the flexing of the shaft, to have the flexible shaft run Yat too high a 'speed and, there- V fore, 'a further object of our inprovenient is to provide ahigh speed handpieee, et

coiiil'aact "construction, .Whereby the speed of the tool may be iiiultiplied considerably, While voperating"the flexible-`shaft at normal fs'peed.l ltfWillbe understood that our high speed Aha'nd piece may be'constructed and usedas'a single unit or it may loe in'ade A as "anattachment `between the flexible shaft l'and our improved cylindrical handpie'c'e.

Vkn'ovvnftd the trade andi inanyof these have "'c'al' shell 'or Casing '1, v'cinnte-rhore :A tiibular 'shaft `4, forming a chuck is rbtatally-inouted 'in the shell "l, the fo'rivard end" tlereoffbeing enlarged Mand bored but to-faceeininedate the cliuck cone type and to"a\foid excessive friction ad v'vear, Ethe rotating' parts thereof are p 'rovided iv1thhallhear1ngs- In the acc'inpany-ingi drawings ,l ive have 'shoiv'n 'the2 preferred "forni of our ini'proved fhan'dfpiec'e; Fig. l representing tliefliigli torylaall bearing for the'hr'gh: speed hand f' speed'han'd piece, in Which'theflexible' shaft are nearly in axial alignment, vthis lieiiig accniplished by utiliing V"an internal frirtiondrive,

'Referring to the drawings and n'ioie par iniprovedf hand' piece coinp-rises 'cyliiidriat each end for the .insertion 'of ball bear cu'p2, invvhich aplur'ali'ty of lo'allsJ 3 `arelocatedn "the 'shank I"of lj'avvs 6. "The clainpiiig nfose T o flthechucl 1sV 'screw-threaded onto IMthe enlarged 'head `5,'as Will'be'seen atV 8. Theeliuck'endof 'cone 'hearing at Slifer Cooperation with the balls 3 'at the 'forwardendof ytheeholl f1.

`The other eiidpfthefshari'l; or"shlaft4"is threaded Aat 10 vand a Cne "bearing li" is mounted thereon for lcoope rati'oi'i ivith ithe balls 3 at the upper end of' the "shelll, siibsta'iitia'llya's shown in Fig. l* of"tlie:draw ings. This provides for the usualadjust-l inentof theball hearings, yand a llock nur 12 is 'provided for "'loclingthe 'cone ybearing in "adusted 'positio n. The upper `'end ofthe Shell lis internally threaded at 13 vand fan annular "thiinble lll Ascrewed therein. The tliiinbleY lll is eereivitliieade'd internally at 15' to receive ltheattacllnient nipple ont?) (of the'ca'sing co'ntainingr the'higlispeed mechanism, or the arinorot' A the. ezible shaft.

VThe 1 tubular ""shaft 4, which fthe 'shank "of 'the chuck 5 2?, is' counter'lbo'red y"at its upper end, at "16, yand'is "provided with a square socket at 1? for receiving the squared end 18 of a stud shaft 19, which passes freely through the screw threaded attachment nipple 2O of the high speed mechanism, as shown in Fig. 1 of the draw- The high speed mechanism is preferably mounted in a. casing formed of two parts 21 and 22, held together by suitable screws The casing member 21 is provided with a boss 24, which is bored out and screw threaded at 25 to receive the attachment nipple 20, the latter also serving to hold in place, a ring type ball bearing 2G, the inner ringl 2T, of which is securely inoanted upon the stud shaft 19, thereby providing a ball bearing for the latter. The upper end of the stud shaft 19 is provided with a friction cone 28, secured ther'eto and held in place by a nut 29. A friction disc or wheel 30 is rotatably supported in the casing member 22, so that the friction face thereof is adapted to engage the friction cone 2S and drive the latter at high speed, since the friction dis@ 30 is of comparatively large diameter. The high speed casing member 22 is bored out at 31 to receive a ball bearing shell or cylinder 32, which, in the present instance, is provided with ball cups 33, cooperating with balls 34. The friction disc or wheel 30 is provided with a shank or stud shaft 35, which has an annular cone bearing at 36 cooperating with the balls 34 of the adjacent ball cup The opposite end of the stud shaft 35 is screw threaded at 37 and carries an adjustable cone bearing 38, which cooperates with the balls 34 of the other ball cup 33, as will be seen in Fig. 1 of the drawings. A lock nut 39 is provided for holding the cone bearing 38 in adjusted position. It will be noticed that this arrangement permits sliding movement of the cylinder 32 in the casing 22, and this is utilized for maintaining pressure between the friction disc 30 and the friction cone 28 to insure satisfactory friction drive. For this purpose, the cylinder 32 is provided with an annular flange 40, against which a compression spring l1 thrusts, the opposite end engaging the casing 22, which is hollowed out at 4:2, as shown in Fig. 1.

The shank or stud shaft 35 of the friction disc 30 is bored out or tubular, substantially similar to the tubular shaft t, forming the shank of the chuck, and is provided with a square socket at 43 of the same size as and corresponding to the square socket 17 in the chuck shank t. The casing member 22 is bored out and threaded at 4A to receive an annular thimble 45, substantially identical with the thimble 14, which is similarly screw-threaded at 46 to receive the attachment nipple 47 of the armor f3 surrounding the flexible shaft 49. The operating end of the flexible shaft 41:9 is provided with a stud shaftor connector plug piece 50, the end of which is squared at 51 to tit the square hole or socket #ii-3, so that the tiembla shaft may drive the friction disc. 30.

ll`he operation of the high speed hand piece will be readily understood from trie description and drawings and it will be seen that the flexible shaft 49 may be run at normal speeds, while the shaft i and chuck 5 7 will run at much higher speed on account of the interposed multiplying gearing of the friction drive 28-30. The arrangement such, however, that by unscrewing the attachment nipple 20. the high speed casingfi and its enclosed mechanism may be removed from the shell 1 of the main hand piece and the screw nipple l? of the flexible shaft may be screwed into place in the thimble 1li of the hand piece. By so doing, the square end 51 of the stud 50 on the fiexible shaft if) will enter the square socket 17 in the chuck shank 4 of the hand piece, thereby providing for direct drive of the chuck from the flexible shaft. he chuck jaws G which, in the present instance, are of the tubular spring chuck type, are preferably removably inserted in the bored out end of the chuck member 5 and are held in place by the clamping nose 7, so that if desired, one set of chuck jaws 6 may be removed at any time by unscrewing the nose 7 and a different set of jaws having a different jaw diameter, inserted therein.

The form of our improved high speed hand piece, as shown in Fig. 2 of the drawings, is substantially the same in construction as that shown in Fig. 1 and the corresponding parts are indicated by the same reference numerals. The main difference is that the anis of the flexible shaft stud is arranged nearly in axial alignment with the axis of the chuck shank -lin the main hand piece. This is accomplished by substituting an internal friction drive wheel :r2 for the disc driving wheel 30 and substituting a conical friction pinion 53, formed with a suitable conical angle for the face thereof to roll on the internal friction surface of the wheel 52, for the small friction cone 23, shown in 1. rfhis straight line form of our high speed hand piece has some advantages and may be preferred over the right angle construction of Fig. 1 in handling certain types of work. The operation, however, of the two devices is substantially the same.

llVhile we have shown our improved hand piece as more particularly adapted for high speed opera-tion, it will be understood that we do not wish to be limited to the specific constru: tion shown, for the high speed mech- '..i n r. ay be considered as an accessory to the regular equipment and attached to the regular stock hand piece whenever it is de- 1,5sass9 aired to operate the tool at high speed, Without incre ng the speed of the flexible shaft. lt will alie be understood that various modifications in the specific details of construction may be n'fade without departing from the spirit and scope of the invention.

l. ,fr "le ible shaft hand piece, comprising a cyliiidrieal shell and a tubular shaft passA ing therethrough, and rotatably mounted therein, one end of said tubular shaft being enlarged and formed a chuck While the other end thereof is adapted to be engaged by the stad end of the flexible shaft.

A fienible shaft hand piece, comprising a cylindrical shell, a tubular shaft rotatably mounted therein7 said shaft being enlarged at one end and formed chuck, the oppoeite end beingprovided With a Vsquare socket for receiving' the. stud end of the flexible shaft, and cup and cone ball bearings between said shell and said shaft.

3. A. flexible Shaft hand piece7 comprising a cylindrical shell, a chuck the shank of which is rotatably mounted in said shell, ball bearings between said shell and the chuck sha-nk, a square socket formed in the end of the clinch shank for receiving the squared stud end of the lieibie shaft and intermediate high speed gea-ring between the shaft and said chuck shank.

A flexible shaft hand piece, comprising a bill bearing rotatable chuck hand piece, an intermediate high Speed gear mechanism attached to said hand piece, means for driving said high speed gearing` from the flexible shalt and means for drivii'ig said chuck from the high speed gearing.

5. The flexible shaft hand piece as claimed in claim Il, in -which the high speed gearing comprises a large -friction Wheel adapted to be driven by the flexible shaft and a small friction cone driven by said wheel, and means operatively connecting said friction cone with said ehuch.

6. flexible shaft hand piece, comprising a cylindrical shell, rotatable chuck member mounted therein, a high speed n'leehanism therefor, provided with a casing removably secured to said shell, inelnding multiplying' gear devices Within said casing and a high speed stud shaft operated thereby and adapted to engage and drive said chuck and means `for driving said high speed gear mechanism from the stud end of said lieXi'ble shaft.

'7'. A flexible shaft hand piece, comprising a caring, chuck member rotatably mounted in said casing, high speed gearing operatively connected with said chuck member, means operatively Connecting said high speed gearing With the stud end of the flexible shaft, and ball bearings between the casing and said' high speed mechanism.

The flexible shalt hand piece, as claimed in claim 7, in which the high speed 1nechanism comprises a friction cone driven by friction dise and a spring is provided Within the easing for holding the dise in contact with the friction cone.

9. A flexible shaft hand piece, eoi'i'iprising cylindrical shell, a chuck the shank of which is rotatably mounted on ball bearings in said shell, a casing removably attached to one end ol' said shell, a high Speed stud shaft in said casing to operatively engage and drive said clinch, a friction cone secured to said stud shaft, a friction disc adapted to engage saitl cone for driving the latter at high speed, ball bearings for rotatably snporting said friction disc in the casing7 a spring engaging the casing and thrusting said'dise against the cone and means for driving said disc from the flexible shaft.

l0. The flexible shaft hand piece, as claimed in claim 9, in which the stud end of the flexible shaft and the end of said high speed stud shaft are provided with similar squared ends and the shank ol said chuck and the high speed disc are eaeh provided with similar square sockets, whereby the high speed easing may be removed from said shell and the flexible shaft operatively connected directly to the shank of said chuclr.

JGSEPH F. KELLER. ALiVlN B. BCllh/Uillll. 

